JP7444288B2 - Communication control device, communication control system, communication control method, and communication control program - Google Patents

Description

The present disclosure relates to a communication control device, a communication control system, a communication control method, and a communication control program.

Non-Patent Document 1 and Non-Patent Document 2 disclose examples of communication systems. In a communication system, a PON (Passive Optical Network) including a plurality of ONUs (Optical Network Units) and OLTs (Optical Line Terminals) is constructed. In a communication system, TDMA (Time Division Multiple Access) technology is used for uplink communication from ONU to OLT. The OLT of Non-Patent Document 1 includes an OLT server, a NIC (Network Interface Card), and a TRx (Transceiver).

T. Tochino et al., "Redesigned TDM-PON System Architecture Based on Point-to-Point Ethernet Transmission and Software Processing with General-purpose Hardware," Journal of Lightwave Technology, 2020. IEEE Standard for Ethernet, SECTION FIVE, IEEE 802.3, 2015.

However, in the communication system of Non-Patent Document 1, Ethernet LFS (Link Fault Signaling) operates in the NIC of the OLT between frames from the ONU. At this time, since L2 (Layer-2) frames cannot be transmitted, the band usage efficiency decreases.

The present disclosure relates to solving such problems. The present disclosure provides a communication control device, a communication control system, a communication control method, and a communication control program that make it difficult to reduce band utilization efficiency.

The communication control device according to the present disclosure includes a transmission time storage unit that stores a transmission time of an optical signal between each of the plurality of ONUs, and a synchronization process is completed after receiving the optical signal of each of the plurality of ONUs. a synchronization time acquisition unit that acquires the synchronization time until the transmission of the optical signal; an optical transmission control unit that generates control information that is transmitted to the plurality of ONUs and controls the start and end of transmission of an optical signal in each of the plurality of ONUs; The control information generated by the optical transmission control unit and the transmission time storage unit for the first ONU stores a first time at which reception of the optical signal from the first ONU among the plurality of ONUs ends. A second time at which synchronization processing ends after starting reception of an optical signal from a second ONU that transmits an optical signal next to the first ONU among the plurality of ONUs, calculated using the transmission time between is calculated using the synchronization time acquired by the synchronization time acquisition unit, and the failure detection unit that detects a link failure with the plurality of ONUs detects a link failure between the first time and the second time. and a failure detection suppression unit that suppresses detection of the failure detection.

A communication control system according to the present disclosure includes the communication control device described above and a failure detection unit that detects a link failure between the plurality of ONUs.

A communication control method according to the present disclosure includes a transmission time storage step of storing a transmission time of an optical signal between each of the plurality of ONUs, and a transmission time storage step of storing the transmission time of an optical signal between each of the plurality of ONUs, and receiving the optical signal of each of the plurality of ONUs. a synchronization time acquisition step of acquiring a synchronization time from to the end of synchronization processing, and an optical signal that is transmitted to the plurality of ONUs and generates control information that controls the start and end of transmission of an optical signal in each of the plurality of ONUs. a transmission control step; a first time at which reception of an optical signal from a first ONU among the plurality of ONUs is terminated; control information generated in the optical transmission control step and the transmission time storage step for the first ONU; a first calculation step of calculating using the transmission time between the first ONU and the first ONU stored in the first calculation step; and a first calculation step of calculating the transmission time between the first ONU and the second ONU that transmits the optical signal after the first ONU among the plurality of ONUs. a second calculation step of calculating a second time at which the synchronization process ends after it has started, using the synchronization time acquired in the synchronization time acquisition step; and a failure of detecting a link failure between the plurality of ONUs. a failure detection suppression step of causing the detection unit to specify a period from the first time calculated in the first calculation step to the second time calculated in the second calculation step to suppress detection of a link failure; , is a method of executing.
A communication control method according to the present disclosure includes a transmission time storage step of storing a transmission time of an optical signal between each of the plurality of ONUs, and a transmission time storage step of storing the transmission time of an optical signal between each of the plurality of ONUs, and receiving the optical signal of each of the plurality of ONUs. a synchronization time acquisition step of acquiring a synchronization time from to the end of synchronization processing, and an optical signal that is transmitted to the plurality of ONUs and generates control information that controls the start and end of transmission of an optical signal in each of the plurality of ONUs. a transmission control step; a first time at which reception of an optical signal from a first ONU among the plurality of ONUs is terminated; control information generated in the optical transmission control step and the transmission time storage step for the first ONU; a first calculation step of calculating using the transmission time between the first ONU and the first ONU stored in the first calculation step; and a first calculation step of calculating the transmission time between the first ONU and the second ONU that transmits the optical signal after the first ONU among the plurality of ONUs. a second calculation step of calculating a second time at which the synchronization process ends after it has started, using the synchronization time acquired in the synchronization time acquisition step; and a failure of detecting a link failure between the plurality of ONUs. a suppression start step of causing the detection unit to start suppressing detection of a link failure from the first time calculated in the first calculation step; and a step of terminating the suppression of link failure detection at the specified time.

A communication control program according to the present disclosure includes a transmission time storage step of storing, in a communication control device, a transmission time of an optical signal between each of the plurality of ONUs, and receiving the optical signal of each of the plurality of ONUs. a synchronization time acquisition step of acquiring a synchronization time from to the end of synchronization processing, and an optical signal that is transmitted to the plurality of ONUs and generates control information that controls the start and end of transmission of an optical signal in each of the plurality of ONUs. a transmission control step; a first time at which reception of an optical signal from a first ONU among the plurality of ONUs is terminated; control information generated in the optical transmission control step and the transmission time storage step for the first ONU; a first calculation step of calculating using the transmission time between the first ONU and the first ONU stored in the first calculation step; and a first calculation step of calculating the transmission time between the first ONU and the second ONU that transmits the optical signal after the first ONU among the plurality of ONUs. a second calculation step of calculating a second time at which the synchronization process ends after it has started, using the synchronization time acquired in the synchronization time acquisition step; and a failure of detecting a link failure between the plurality of ONUs. a failure detection suppression step of causing the detection unit to specify a period from the first time calculated in the first calculation step to the second time calculated in the second calculation step to suppress detection of a link failure; This is a program that executes .
A communication control program according to the present disclosure includes a transmission time storage step of storing, in a communication control device, a transmission time of an optical signal between each of the plurality of ONUs, and receiving the optical signal of each of the plurality of ONUs. a synchronization time acquisition step of acquiring a synchronization time from to the end of synchronization processing, and an optical signal that is transmitted to the plurality of ONUs and generates control information that controls the start and end of transmission of an optical signal in each of the plurality of ONUs. a transmission control step; a first time at which reception of an optical signal from a first ONU among the plurality of ONUs is terminated; control information generated in the optical transmission control step and the transmission time storage step for the first ONU; a first calculation step of calculating using the transmission time between the first ONU and the first ONU stored in the first calculation step; and a first calculation step of calculating the transmission time between the first ONU and the second ONU that transmits the optical signal after the first ONU among the plurality of ONUs. a second calculation step of calculating a second time at which the synchronization process ends after it has started, using the synchronization time acquired in the synchronization time acquisition step; and a failure of detecting a link failure between the plurality of ONUs. a suppression start step of causing the detection unit to start suppressing detection of a link failure from the first time calculated in the first calculation step; This program executes a suppression termination step of terminating suppression of link failure detection at a specified time.

According to the communication control device, communication control system, communication control method, or communication control program according to the present disclosure, band utilization efficiency is less likely to decrease.

1 is a configuration diagram of a communication system according to Embodiment 1. FIG. 1 is a diagram illustrating an example of the configuration of an OLT according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating an example of communication control in the communication system according to the first embodiment. 3 is a flowchart illustrating an example of the operation of the OLT server according to the first embodiment. 7 is a flowchart illustrating an example of the operation of the OLT server according to the second embodiment.

Embodiments of the present disclosure will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are given the same reference numerals, and overlapping explanations are simplified or omitted as appropriate. Note that the present disclosure is not limited to the following embodiments, and any combination of embodiments, modifications of any constituent elements of each embodiment, or modifications to each embodiment may be made without departing from the spirit of the present disclosure. Any component of the embodiment can be omitted.

Embodiment 1.
FIG. 1 is a configuration diagram of a communication system 1 according to the first embodiment.

In the communication system 1, a PON 2 is constructed. The PON 2 includes a plurality of ONUs 3, an OLT 4, and an optical splitter 5. Each ONU 3 is connected to an optical splitter 5 by an optical communication line 6. The optical communication line 6 is, for example, an optical fiber cable. The OLT 4 is connected to the optical branching device 5 by an optical communication line 6. The optical splitter 5 is an optical passive component such as an optical coupler or an optical splitter. Each ONU 3 and OLT 4 communicates optical signals through an optical communication line 6 and an optical branching device 5. In the communication system 1, TDMA technology is used for upstream communication from the ONU 3 to the OLT 4.

Each ONU 3 is placed at a base or residence of a subscriber who receives communication services in the communication system 1. Each ONU 3 is a device that converts an electrical signal from a network used by a subscriber into an optical signal and transmits the optical signal to the OLT 4 in uplink communication of the PON 2 . The network used by the subscriber is, for example, a LAN (Local Area Network). Each ONU 3 includes a TRx 7a, a NIC 8a, and an ONU server 9a. The TRx7a is a device equipped with a function of mutually converting electrical signals and optical signals. The NIC 8a is a device equipped with a function of processing communication according to a standard such as, for example, Ethernet (registered trademark). The ONU server 9a is a device equipped with a function of controlling communication with the OLT 4 via the NIC 8a and the TRx 7a.

The OLT 4 is placed at a base of a business operator that provides communication services in the communication system 1 . The OLT 4 is a device that receives optical signals from each ONU 3 and converts the optical signals into electrical signals for the upper network etc. in upstream communication of the PON 2. The upper network is, for example, the Internet. The OLT 4 includes a TRx 7b, a NIC 8b, and an OLT server 9b. The TRx7b is a device equipped with a function of mutually converting electrical signals and optical signals. The NIC 8b is a device equipped with a function of processing communication according to a standard such as, for example, Ethernet. The OLT server 9b is a device equipped with a function of controlling communication between the NIC 8b and each ONU 3 via the TRx 7b. The OLT server 9b is an example of a communication control device. OLT4 is an example of a communication control system.

FIG. 2 is a diagram showing an example of the configuration of the OLT 4 according to the first embodiment.

The NIC 8b has an Ethernet section 10. The Ethernet unit 10 is a part that processes Ethernet frames. The Ethernet unit 10 is, for example, an Ethernet Controller in the NIC 8b. The Ethernet section 10 includes a failure detection section 11. The failure detection unit 11 is a part that detects a link failure with each ONU 3. In this example, the failure detection unit 11 is a part that performs, for example, LFS processing defined in Ethernet. The link failure detected by the failure detection unit 11 includes, for example, a situation of collision of optical signals received from a plurality of ONUs 3 at the same time. Further, the link failure detected by the failure detection unit 11 includes, for example, a situation in which an optical signal is not received from any ONU 3.

The OLT server 9b includes a transmission time storage section 12, an optical transmission control section 13, a synchronization time acquisition section 14, and a failure detection suppression section 15. Each function of the optical transmission control unit 13, transmission time storage unit 12, synchronization time acquisition unit 14, failure detection suppression unit 15, etc. of the OLT server 9b is executed based on, for example, a communication control program installed in the OLT server 9b. be done. The communication control program installed in the OLT server 9b may be recorded on a recording medium, for example.

The transmission time storage section 12 is a section that stores information. In the transmission time storage unit 12, the transmission time of the optical signal between the OLT 4 and each ONU 3 is stored. The transmission time with each ONU 3 is measured, for example, when the ONU 3 is connected. The transmission time is, for example, RTT (Round Trip Time) obtained in Ethernet. The measured transmission time is stored in the transmission time storage section 12. The transmission time with each ONU 3 may be updated every time there is communication with the ONU 3.

The optical transmission control unit 13 is a part that generates control information that controls the start and end of transmission of optical signals in each ONU 3. Control information is transmitted to each ONU 3 through the NIC 8b, the TRx 7b, the optical communication line 6, the optical branching device 5, and the like. The control information is, for example, an Ethernet GATE frame. The control information transmitted to each ONU 3 includes information such as whether or not the ONU 3 can transmit an optical signal, the transmission start time of the optical signal, and the duration of transmission of the optical signal. The control information may include information on the transmission time stored in the transmission time storage section 12. The optical transmission control unit 13 generates control information based on transmission request information received from each ONU 3, for example. The transmission request information is, for example, an Ethernet REPORT frame.

The synchronization time acquisition unit 14 is a part that acquires synchronization time. The synchronization time is the time from when the optical signal of each ONU 3 is received until the synchronization process ends. The synchronization time may be a time starting from a time when the output of the received optical signal becomes stable. The starting point of the synchronization time is, for example, the time point when the output of the LOS pin of TRx7b is switched. The end of the synchronization time is, for example, the time when the NIC 8b detects Ethernet synchronization. Here, if the NIC 8b becomes out of synchronization with the Ethernet, for example in a link failure situation in which no optical signal is received from any ONU 3, the NIC 8b performs a link down due to LFS. Thereafter, the NIC 8b is linked up when Ethernet synchronization is achieved. The synchronization time acquisition unit 14 acquires the synchronization time using, for example, the timing of this link up as the end point. The synchronization time acquisition unit 14 acquires the synchronization time by calculation, for example. Alternatively, the synchronization time acquisition unit 14 may acquire the value of the synchronization time used for communication control based on the measured value of the past synchronization time.

The failure detection suppressing unit 15 is a part that suppresses detection of a link failure by the failure detecting unit 11. The failure detection suppressing unit 15 outputs a control command to the failure detecting unit 11 to suppress detection of a link failure, specifying, for example, a period from a first time to a second time. The failure detection unit 11 is equipped with a function of calculating a first time and a second time.

Next, an example of the hardware configuration of the communication system 1 including the OLT 4 and each ONU 3 will be described. Devices of the communication system 1 include, for example, an OLT server 9b, NIC8b, and TRx7b, and an ONU server 9a, NIC8a, and TRx7a. The device of the communication system 1 has, as hardware, a processing circuit including, for example, a processor and a memory. The processor is, for example, a CPU, an arithmetic unit, a microprocessor, or a microcomputer. Examples of the memory include nonvolatile or volatile semiconductor memories such as RAM, ROM, flash memory, EPROM, and EEPROM, or magnetic disks, flexible disks, optical disks, compact disks, minidisks, or DVDs. The memory stores programs such as software or firmware. The device of the communication system 1 executes preset processing by having a processor execute a program stored in the memory, and realizes each function as a result of cooperation between hardware and software. Each function of the device of the communication system 1 may be realized by a processing circuit. Alternatively, some or all of the functions of the devices of the communication system 1 may be realized by a processing circuit. Additionally, the processing circuitry may be implemented as, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, or an FPGA, or a combination thereof.

Next, an example of suppressing link failure detection will be described using FIG. 3.
FIG. 3 is a diagram illustrating an example of communication control in the communication system 1 according to the first embodiment.
In FIG. 3, the horizontal axis represents time.

When each ONU 3 is connected to the PON 2, the transmission time is measured by the round trip of the optical signal between the ONU 3 and the OLT 4. The OLT server 9b acquires information represented by the optical signal from each ONU 3 through the TRx 7b and the NIC 8b. The transmission time storage unit 12 of the OLT server 9b stores the transmission time measured here.

In this example, each ONU 3 connected to PON 2 transmits optical signals to OLT 4 in burst mode. Each ONU 3 transmits transmission request information to the OLT 4 based on the amount of data received from the network used by the subscriber.

The optical transmission control unit 13 of the OLT server 9b allocates a band to each ONU 3 based on the transmission request information received from each ONU 3. The optical transmission control unit 13 generates control information to be transmitted to each ONU 3 based on the allocated band. The optical transmission control unit 13 transmits control information to each ONU 3 through the NIC 8b and TRx 7b.

The failure detection and suppression unit 15 calculates the first time and the second time, for example, when the optical transmission control unit 13 generates control information. Here, the first time and the second time are calculated for each set of the ONU 3 that transmits the optical signal first and the ONU 3 that transmits the optical signal next for the plurality of ONUs 3 that sequentially transmit the optical signal. The ONU 3 that transmits the optical signal first is an example of the first ONU. The ONU 3 that transmits the optical signal next is an example of a second ONU. In this example, ONU 3q transmits the optical signal next to ONU 3p.

The failure detection suppression unit 15 calculates the first time using the control information and the transmission time. The failure detection suppressing unit 15 calculates the time when the OLT 4 finishes receiving the optical signal from the ONU 3p, using, for example, the transmission start time and transmission duration in the control information for the ONU 3p, and the transmission time with the ONU 3p. The failure detection suppressing unit 15 sets the time calculated here as the first time for the set of ONU 3p and ONU 3q.

The failure detection suppression unit 15 calculates the first time using the synchronization time. The failure detection suppression unit 15 starts receiving the optical signal from the ONU 3q using, for example, the transmission start time in the control information to the ONU 3q, the transmission time with the ONU 3q, and the synchronization time acquired by the synchronization time acquisition unit 14. Later, calculate the time when the synchronization process ends. The failure detection suppressing unit 15 sets the time calculated here as the second time for the set of ONU 3p and ONU 3q.

The failure detection suppressing unit 15 outputs a control command to the failure detecting unit 11 to specify a period from the calculated first time to the second time for the set of ONU 3p and ONU 3q, and to suppress detection of a link failure. The failure detection suppressing unit 15 similarly outputs control commands to the failure detecting unit 11 for other sets of ONUs 3.

After that, if the control information received from the OLT 4 indicates that the optical signal can be transmitted, the ONU 3p starts transmitting the optical signal from the transmission start time. The ONU 3p ends the transmission of the optical signal when the transmission duration time of the control information has elapsed.

The OLT 4 finishes receiving the optical signal from the ONU 3p after a transmission time delay from the time when the ONU 3p finishes transmitting the optical signal. Since this time is the first time, the failure detection suppressing unit 15 starts suppressing link failure detection from this time.

At this time, the OLT 4 does not receive an optical signal from any ONU 3, but the period is within the period specified in the control command received from the failure detection suppressing unit 15, so the failure detecting unit 11 does not detect a link failure.

After that, if the control information received from the OLT 4 indicates that the optical signal can be transmitted, the ONU 3q starts transmitting the optical signal from the transmission start time. The ONU 3q may transmit the idle signal until the synchronization time included in the control information has elapsed. At this time, the ONU 3q starts transmitting the data signal after the synchronization time has elapsed. Here, the data signal is an optical signal containing data from a network connected to ONU 3q to a network connected to OLT 4.

The OLT 4 starts receiving the optical signal from the ONU 3q after a transmission time delay from the time when the ONU 3q starts transmitting the optical signal. Then, after the synchronization time has elapsed, the OLT 4 starts receiving data signals from the ONU 3q. Since this time is the second time, the failure detection suppression unit 15 ends the suppression of link failure detection at this time.

At this time, since the period specified in the control command received from the failure detection suppression unit 15 has ended, the failure detection unit 11 detects link failure.

Next, an example of the operation of the OLT server 9b will be described using FIG. 4.
FIG. 4 is a flowchart showing an example of the operation of the OLT server 9b according to the first embodiment.

In step S1, the transmission time storage unit 12 stores the transmission time measured with each ONU 3. After that, in step S2, the synchronization time acquisition unit 14 acquires the synchronization time in the OLT 4. After that, in step S3, the optical transmission control unit 13 generates control information for each ONU 3. The generated control information is transmitted to each ONU 3. Thereafter, in step S4, the failure detection suppression unit 15 calculates a first time. Thereafter, in step S5, the failure detection suppression unit 15 calculates a second time. After that, in step S6, the failure detection suppressing unit 15 causes the failure detecting unit 11 to suppress detection of link failure by outputting a control command specifying a period from the first time to the second time. Thereafter, the failure detection unit 11 suppresses detection of link failure for a specified period of time.

Here, step S2 may be executed before step S1. Step S1 and step S2 may be appropriately omitted after being executed once. Step S5 may be executed before step S4. In addition, the order of execution of each step may be changed as appropriate without departing from the spirit of the present disclosure. Further, each step may be executed in parallel as appropriate without departing from the spirit of the present disclosure.

As described above, the OLT 4 according to the first embodiment includes the NIC 8b having the failure detection unit 11 and the OLT server 9b, which is an example of a communication control device. The failure detection unit 11 detects a link failure between the ONU 3 connected to the OLT 4 and the ONU 3 connected to the OLT 4 . The OLT server 9b includes a transmission time storage section 12, a synchronization time acquisition section 14, an optical transmission control section 13, and a failure detection suppression section 15. The transmission time storage unit 12 stores the transmission time of the optical signal between each ONU 3 and OLT 4. The synchronization time acquisition unit 14 acquires the synchronization time from receiving the optical signal of each ONU 3 until the synchronization process ends. The optical transmission control unit 13 generates control information to be transmitted to the plurality of ONUs 3. The control information is information that controls the start and end of transmission of optical signals in each ONU 3. Among the plurality of ONUs 3, ONU 3q transmits an optical signal next to ONU 3p. The failure detection suppressing unit 15 calculates a first time at which the reception of the optical signal from the ONU 3p ends. The first time is calculated using the control information generated by the optical transmission control unit 13 for the ONU 3p and the transmission time between the ONU 3p and the ONU 3p stored in the transmission time storage unit 12. The failure detection suppressing unit 15 calculates a second time at which the synchronization process ends after starting to receive the optical signal from the ONU 3q. The second time is calculated using the synchronization time acquired by the synchronization time acquisition unit 14. The failure detection suppression unit 15 causes the failure detection unit 11 to suppress link failure detection from the first time to the second time.
Further, the failure detection suppressing unit 15 causes the failure detecting unit 11 to suppress detection of a link failure by outputting a control command specifying a period from the first time to the second time.
Further, in the communication control method according to the first embodiment, the OLT server 9b performs a transmission time storage step, a synchronization time acquisition step, an optical transmission control step, a first calculation step, a second calculation step, and a failure detection step. and a method for performing the suppression step. The transmission time storage step is a step of storing the transmission time for each ONU 3. The synchronization time acquisition step is a step of acquiring synchronization time in the OLT 4. The optical transmission control step is a step of generating control information to be transmitted to the plurality of ONUs 3. The first calculation step is a step of calculating a first time for the ONU 3p. The second calculation step is a step of calculating a second time for the ONU 3q. The failure detection suppression step specifies a period from the first time calculated in the first calculation step to the second time calculated in the second calculation step, and causes the failure detection unit 11 to suppress detection of the link failure. It is a step.
The communication control program according to the first embodiment also includes a transmission time storage step, a synchronization time acquisition step, an optical transmission control step, a first calculation step, a second calculation step, and a failure detection step in the OLT server 9b. This is a program that executes a suppression step.

With such a configuration, detection of a link failure is suppressed between frames in which data signals are transmitted in burst mode or the like. Therefore, even if the OLT 4 does not receive an optical signal between these frames, no link failure is detected. Therefore, since the transmission of L2 frames is not suppressed, band usage efficiency is less likely to decrease. Furthermore, link failure detection is effective while a frame including a data signal is being transmitted. Therefore, when a link failure actually occurs, processing corresponding to the link failure can be appropriately performed in the communication system 1.

Embodiment 2.
In Embodiment 2, points that are different from the example disclosed in Embodiment 1 will be explained in particular detail. As for the features not described in the second embodiment, any of the features in the examples disclosed in the first embodiment may be adopted.

FIG. 5 is a flowchart showing an example of the operation of the OLT server 9b according to the second embodiment.

The OLT server 9b according to the second embodiment operates in the same manner as the OLT server 9b according to the first embodiment from step S1 to step S5. After the second time is calculated in step S5, the operation of the OLT server 9b according to the second embodiment proceeds to step S7. In step S7, the failure detection suppressing unit 15 causes the failure detecting unit 11 to start suppressing link failure detection from the first time by outputting a control command specifying the first time. Thereafter, the failure detection unit 11 starts suppressing link failure detection from the first time. In step S8, the failure detection suppressing unit 15 causes the failure detecting unit 11 to end suppressing link failure detection at the second time by outputting a control command specifying the second time. Thereafter, the failure detection unit 11 ends the suppression of link failure detection at the second time.

Here, step S5 may be executed after step S7. At this time, step S2 may be executed after step S7. For example, at least either step S2 or step S5 may be executed when the output of the optical signal from the ONU 3q becomes stable. In this case, the failure detection suppression unit 15 does not need to use the transmission time and control information to calculate the second time. In addition, the order of execution of each step may be changed as appropriate without departing from the spirit of the present disclosure. Further, each step may be executed in parallel as appropriate without departing from the spirit of the present disclosure.

As described above, in the OLT 4 according to the second embodiment, the failure detection suppressing unit 15 causes the failure detecting unit 11 to start suppressing link failure detection by outputting a control command specifying the first time. The failure detection suppressing unit 15 causes the failure detecting unit 11 to end suppressing link failure detection by outputting a control command specifying the second time.
Further, in the communication control method according to the second embodiment, the OLT server 9b performs a transmission time storage step, a synchronization time acquisition step, an optical transmission control step, a first calculation step, a second calculation step, and a suppression start. and a suppression termination step. The suppression start step is a step for causing the failure detection unit 11 to start suppressing link failure detection from the first time calculated in the first calculation step. The suppression termination step is a step of causing the failure detection unit 11 to terminate suppression of link failure detection at the second time calculated in the second calculation step.
The communication control program according to the second embodiment also includes a transmission time storage step, a synchronization time acquisition step, an optical transmission control step, a first calculation step, a second calculation step, and a suppression start in the OLT server 9b. This is a program that executes a step and a suppression end step.

With such a configuration, detection of a link failure is suppressed between frames in which data signals are transmitted in burst mode or the like. Therefore, even if the OLT 4 does not receive an optical signal between these frames, no link failure is detected. Therefore, since the transmission of L2 frames is not suppressed, band usage efficiency is less likely to decrease. Furthermore, link failure detection is effective while a frame including a data signal is being transmitted. Therefore, when a link failure actually occurs, processing corresponding to the link failure can be appropriately performed in the communication system 1.

The communication control system according to the present disclosure can be applied to a communication system. The communication control device according to the present disclosure can be applied to the communication control system. The communication control method according to the present disclosure can be applied to a communication system including the communication control device. The communication control program according to the present disclosure can be applied to the communication control device.

1 communication system, 2 PON, 3 ONU, 4 OLT, 5 optical branch, 6 optical communication line, 7a, 7b TRx, 8a, 8b NIC, 9a ONU server, 9b OLT server, 10 Ethernet section, 11 failure detection section, 12 Transmission time storage unit, 13 Optical transmission control unit, 14 Synchronization time acquisition unit, 15 Failure detection suppression unit

Claims (8)

a transmission time storage unit that stores the transmission time of the optical signal between each of the plurality of ONUs;
a synchronization time acquisition unit that acquires the synchronization time from receiving the optical signal of each of the plurality of ONUs until the synchronization process ends;
an optical transmission control unit that generates control information that is transmitted to the plurality of ONUs and controls the start and end of transmission of optical signals in each of the plurality of ONUs;
The control information generated by the optical transmission control unit and the transmission time storage unit for the first ONU stores a first time at which reception of the optical signal from the first ONU among the plurality of ONUs ends. A second time at which synchronization processing ends after starting reception of an optical signal from a second ONU that transmits an optical signal next to the first ONU among the plurality of ONUs, calculated using the transmission time between is calculated using the synchronization time acquired by the synchronization time acquisition unit, and the failure detection unit that detects a link failure with the plurality of ONUs detects a link failure between the first time and the second time. a failure detection suppression unit that suppresses detection of the
A communication control device comprising: The communication control device according to claim 1, wherein the failure detection suppressing unit causes the failure detecting unit to suppress detection of a link failure by outputting a control command specifying a period from the first time to the second time. The failure detection suppression unit causes the failure detection unit to start suppressing link failure detection by outputting a control command specifying the first time, and causes the failure detection unit to start suppressing link failure detection by outputting a control command specifying the second time. The communication control device according to claim 1, wherein the suppression of link failure detection is terminated. A communication control device according to any one of claims 1 to 3,
a failure detection unit that detects a link failure between the plurality of ONUs;
A communication control system equipped with The communication control device
a transmission time storage step of storing the transmission time of the optical signal between each of the plurality of ONUs;
a synchronization time acquisition step of acquiring synchronization time from receiving the optical signal of each of the plurality of ONUs until the synchronization process ends;
an optical transmission control step of generating control information that is transmitted to the plurality of ONUs and controls the start and end of transmission of optical signals in each of the plurality of ONUs;
A first time at which reception of an optical signal from a first ONU among the plurality of ONUs ends is determined by the control information generated in the optical transmission control step and the control information stored in the transmission time storage step for the first ONU. A first calculation step of calculating using the transmission time with the first ONU;
A second time at which the synchronization process ends after starting reception of an optical signal from a second ONU that transmits an optical signal next to the first ONU among the plurality of ONUs is determined by the synchronization acquired in the synchronization time acquisition step. a second calculation step of calculating using time;
A period from the first time calculated in the first calculation step to the second time calculated in the second calculation step is specified to a failure detection unit that detects a link failure between the plurality of ONUs. a failure detection suppression step for suppressing detection of a link failure;
A communication control method that performs The communication control device
a transmission time storage step of storing the transmission time of the optical signal between each of the plurality of ONUs;
a synchronization time acquisition step of acquiring synchronization time from receiving the optical signal of each of the plurality of ONUs until the synchronization process ends;
an optical transmission control step of generating control information that is transmitted to the plurality of ONUs and controls the start and end of transmission of optical signals in each of the plurality of ONUs;
A first time at which reception of an optical signal from a first ONU among the plurality of ONUs ends is determined by the control information generated in the optical transmission control step and the control information stored in the transmission time storage step for the first ONU. A first calculation step of calculating using the transmission time with the first ONU;
A second time at which the synchronization process ends after starting reception of an optical signal from a second ONU that transmits an optical signal next to the first ONU among the plurality of ONUs is determined by the synchronization acquired in the synchronization time acquisition step. a second calculation step of calculating using time;
a suppression start step of causing a failure detection unit that detects a link failure between the plurality of ONUs to start suppressing detection of a link failure from the first time calculated in the first calculation step;
a suppression termination step of causing the failure detection unit to terminate suppression of link failure detection at the second time calculated in the second calculation step;
A communication control method that performs In the communication control device,
a transmission time storage step of storing the transmission time of the optical signal between each of the plurality of ONUs;
a synchronization time acquisition step of acquiring synchronization time from receiving the optical signal of each of the plurality of ONUs until the synchronization process ends;
an optical transmission control step of generating control information that is transmitted to the plurality of ONUs and controls the start and end of transmission of optical signals in each of the plurality of ONUs;
A first time at which reception of an optical signal from a first ONU among the plurality of ONUs ends is determined by the control information generated in the optical transmission control step and the control information stored in the transmission time storage step for the first ONU. A first calculation step of calculating using the transmission time with the first ONU;
A second time at which the synchronization process ends after starting reception of an optical signal from a second ONU that transmits an optical signal next to the first ONU among the plurality of ONUs is determined by the synchronization acquired in the synchronization time acquisition step. a second calculation step of calculating using time;
A period from the first time calculated in the first calculation step to the second time calculated in the second calculation step is specified to a failure detection unit that detects a link failure between the plurality of ONUs. a failure detection suppression step for suppressing detection of a link failure;
A communication control program that executes. In the communication control device,
a transmission time storage step of storing the transmission time of the optical signal between each of the plurality of ONUs;
a synchronization time acquisition step of acquiring synchronization time from receiving the optical signal of each of the plurality of ONUs until the synchronization process ends;
an optical transmission control step of generating control information that is transmitted to the plurality of ONUs and controls the start and end of transmission of optical signals in each of the plurality of ONUs;
A first time at which reception of an optical signal from a first ONU among the plurality of ONUs ends is determined by the control information generated in the optical transmission control step and the control information stored in the transmission time storage step for the first ONU. A first calculation step of calculating using the transmission time with the first ONU;
A second time at which the synchronization process ends after starting reception of an optical signal from a second ONU that transmits an optical signal next to the first ONU among the plurality of ONUs is determined by the synchronization acquired in the synchronization time acquisition step. a second calculation step of calculating using time;
a suppression start step of causing a failure detection unit that detects a link failure between the plurality of ONUs to start suppressing detection of a link failure from the first time calculated in the first calculation step;
a suppression termination step of causing the failure detection unit to terminate suppression of link failure detection at the second time calculated in the second calculation step;
A communication control program that executes.

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